After more than a week of growing criticism of his support for a flawed surveillance bill, Barack Obama quietly responded late Thursday evening. He's not likely to quell his growing cadre of critics.

In a blog response posted just before 5 p.m. headed into a three-day holiday weekend, Obama reiterated his support for an update to the Foreign Intelligence Surveillance Act the Senate is expected to vote on Tuesday. (No mention of the blog post seems to have been distributed to Obama's normal press list, either.)

Obama says he is against a provision in the bill to give legal immunity to telecommunications companies that facilitated the National Security Agency's warrantless surveillance of Americans as authorized by President Bush. He vowed to support amendments that would strip immunity but would vote for the final bill regardless.

"It's a stiff arm to the people that care about the Constitution," said Mike Stark, a blogger and liberal activist who started a group on Obama's social networking page to urge him to fix the FISA bill.

"It's left a question in a lot of people's mind about how committed he really is to change," Stark told RAW STORY.

Responding to the 17,000 supporters who made the group the largest on my.barackobama.com, the Democratic candidate said he was glad to hear their concerns but reminded them that they really didn't have any other choice in this election.

"I think it is worth pointing out that our agreement on the vast majority of issues that matter outweighs the differences we may have," Obama wrote. "After all, the choice in this election could not be clearer."

Justifying his support for the FISA bill, Obama cited a provision in the latest version that provides FISA is the "exclusive means" through which a president can authorize surveillance. Of course, the original FISA bill, passed in 1978, had the same qualification, and three federal judges have ruled that President Bush did not have inherent authority to conduct warrantless surveillance like he claimed to have had.

He also noted the fact that surveillance authorizations under the Protect America Act, a stopgap FISA update Obama opposed when it passed last year, would expire in August. Glenn Greenwald debunks this justification here.

If opponents of Bush's warrantless wiretapping program can take any encouragement from Obama's statement, it is that he does repeat earlier pledges to instruct his Attorney General to fully investigate just what Bush authorized, if he's elected.

"Given the choice between voting for an improved yet imperfect bill, and losing important surveillance tools, I've chosen to support the current compromise," he writes. "I do so with the firm intention -- once Iím sworn in as President -- to have my Attorney General conduct a comprehensive review of all our surveillance programs, and to make further recommendations on any steps needed to preserve civil liberties and to prevent executive branch abuse in the future."

Stark allowed that electing Obama remained the larger goal for him, but said the disappointment many feel about his decision to support FISA could linger even if he were elected.

"Of course I'm going to vote for him in November," he said. But "we're keeping score, and there's going to be a time when he needs us. ... We have long memories."